[3-Dimensional irradiation planning in brain tumors. The advantages of the method and the clinical results].
OBJECTIVE
Radiotherapy became an important component in the treatment of brain gliomas. The aim of this study is to analyse several advantages of the three-dimensional conformal radiation therapy in comparison with a two-dimensional conventional technique and to present the clinical results of 43 patients with brain gliomas treated according to a three-dimensional planning.


METHODS
Between January 1994 and December 1995, 43 patients with malignant brain gliomas (WHO III and IV) were treated in our department according to a three-dimensional treatment planning. The patients received a total irradiation dose of 60 Gy, 2 Gy/day, 5 days/week. The rate of survival was analysed in relation with the known prognostical factors: histology, Karnofsky index, age, resection status. In 10 patients a three-dimensional treatment planning was compared with a conventional two-dimensional planning: the volume of the normal brain tissue irradiated to high dose levels (95% isodose) and the normal tissue complication probability (NTCP) for the brain by Kutcher and Lyman were comparatively analysed.


RESULTS
The survival rate for the whole group was 14 months. The histology of the tumor, age, Karnofsky index and resection status were important prognostical factors. The three-dimensional planning allows a 15 to 20% reduction in the volume of normal brain tissue irradiated to high dose levels (95% isodose). The NTCP is significantly lower using the three-dimensional technique (range 0.03% to 13%), in comparison with the two-dimensional conventional technique (range 0.1% to 26%). The value of NTCP increases with tumor volume.


CONCLUSIONS
Concerning the tumor control and survival rate, the three-dimensional treatment planning shows no advantages compared to the standard conventional methods. The main advantage of the three-dimensional treatment planning is the possibility to spare normal brain tissue. The possibility to integrate mathematical models in the evaluation of the therapy could give this technique new dimensions.
Grosu
A L
AL
Klinik und Poliklinik für Strahlentherapie und Radiologische Onkologie, Technische Universität, Klinikum rechts der Isar, München.
Feldmann
H J
HJ
Albrecht
C
C
Kneschaurek
P
P
Wehrmann
R
R
Gross
M W
MW
Zimmermann
F B
FB
Molls
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy*; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging / Q000401:mortality / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011379:Prognosis; D011879:Radiotherapy Dosage; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed
Dreidimensionale Bestrahlungsplanung bei Hirntumoren. Vorteile der Methode und klinische Ergebnisse.